1. Field of Invention
This invention relates generally to transport wheel assemblies for implements adapted for towing and more particularly to an improved wheel assembly for tillage type implements with level action depth control of tools mounted thereon when traveling over uneven terrain and for stability in both working and transport positions.
2. Prior Art
Agricultural type tillage implements are normally designed with substantial widths or lengths transverse to the normal direction of working of the implement for the purpose of covering fairly wide widths in the working of a field. Such implements, because of the increased width of the same, have employed foldable wing sections to enable a reduction in width of the overall implement for transport purposes. The transport wheel assembly for such implements have the normal requirement of positioning the implement relative to the ground surface for proper working depth of the tools mounted thereon and raising of the implement relative to the ground surface for transport purposes. One of the problems encountered in the operation of such an implement is the maintenance of a uniform level of working tool depth into the ground as the implement traverses uneven terrain. This is particularly true in connection with terrain having rocks or bumps therein which will displace the level of the implement as it is being towed in a working mode of operation changing the relationship of the working tools with respect to the ground.
In the past, attempts to maintain the implement operating at a uniform depth of working tool over uneven terrain has been met through the use of a "walking beam" type of transport assembly. In this arrangement, the stablizing or support wheels are mounted in tandem pairs on a common rocker arm so that one wheel of the pair will be free to move up or down to follow the terrain. An example of such a construction is shown in the Erling U.S. Pat. No. 2,734,437. Such a transport wheel arrangement has the problem of creating wheel drag during turns, and like the use of a single wheel, does not provide for uniform distribution of weight throughout the extent of a wide implement. While the walking beam type wheel assembly does provide greater stability than a single wheel support and better traverse over uneven terrain, it still results in angular movement or tilt of the implement relative to the ground when traveling over extremely rough terrain.